High blood pressure is important as if untreated puts you
at greater risk of having a heart attack (myocardial infarction)
or stroke.
To measure blood pressure, two readings are taken:

The systolic pressure. This is the first and higher measurement.
It is a measure of the blood pressure as the heart contracts
and pumps blood out.

The diastolic pressure. This is the second and lower number.
It is a measure of the blood pressure when the heart is relaxed
and filling up with blood.Blood pressure is measured in terms
of millimetres of mercury (mmHg). Hypertension (high blood
pressure) is defined as a systolic pressure of 140 mmHg or
more, or a diastolic pressure of 90 mmHg or more.

Blood pressure varies constantly during the day. The level
of physical exertion, anxiety, stress, emotional changes and
other factors may also cause changes in blood pressure. So
blood pressure should be checked under resting conditions
and single measurements are not particularly meaningful. A
diagnosis of hypertension is not normally made unless a high
blood pressure is measured on three separate occasions (usually
over 3 months).Lifestyle changes, such as a healthy diet and increased
exercise are important for everyone with raised blood pressure.
Medicines to treat hypertension are particularly recommended
for a sustained systolic pressure of 160 mmHg or more and/or
diastolic pressure 100 mmHg or more.

High blood pressure is common. Moderately
high diastolic pressures (90-109 mmHg) are found in about
1 in 4 middle-aged people. They are less common in younger
people and more common in those who are older. Very high diastolic
pressures (110-129 mmHg) are found in about 1 in 25 people.
It is believed that there are large numbers of people who
have high blood pressure but are not aware of it.

Symptoms Most people with hypertension will
not get any symptoms. The only way to find out if you have
high blood pressure is to have it measured.
In rare cases, the blood pressure can rise dramatically and
without warning. The systolic blood pressure can reach 220mmHg
and the diastolic pressure 120mmHg.
Urgent treatment is required. This happens to less than 1
in 100 people who have hypertension. The symptoms of this
type of severe high blood pressure include:
a bad headache, feeling confused, feeling sick, having trouble
seeing, feeling very sleepy.

Causes

High blood pressure is very common, affecting as many as
1 in 4 people.
In approximately 90% of cases, the cause is unknown. This
type of high blood pressure is known as ‘essential hypertension’.
Certain lifestyle and genetic factors may contribute to the
risks of developing essential hypertension.Risk factors include:
getting older, being male - hypertension is slightly more
common in men, having a family member with high blood pressure,
being overweight, drinking excessive amounts of alcohol, stress,
smoking, lack of exercise. ethnic group- as many as half of
all people of black African or Caribbean origin over 40 years
of age are likely to have high blood pressure.

Likewise British people of South Asian (Indian, Pakistani
or Bangladeshi) origin are also more likely to have high blood
pressure and are more prone to stroke and heart attacks.In
a few people, the cause of hypertension can be identified.
The cause may be Cushing's syndrome, kidney disease, taking
certain medicines e.g. oral contraceptives or, rarely, a tumour
of the adrenaline-producing cells in the adrenal gland (small
gland above the kidney).

Treatment

The aim of treatment is to keep the diastolic blood pressure
less than 85mmHg and the systolic blood pressure less than
140 mmHg.
These targets are set slightly lower, diastolic less than
80 mmHg and systolic less than 135 mmHG, for people at greater
risk of heart attack (myocardial infarction) and stroke e.g.
if you have angina, a previous heart attack, chronic renal
failure or diabetes.
In some people, it may not be possible to reduce the blood
pressure below these targets, despite treatment.Lifestyle changes
In many cases, mild high blood pressure can be treated with
lifestyle changes. See the 'Prevention' section.
Losing weight, regular exercise, a low-fat and low salt diet,
quitting smoking and reducing the amount of alcohol consumed
will often be enough to get blood pressure down to normal
levels.Antihypertensive medicines
If lifestyle changes are not successful, then antihypertensive
medicines will be necessary. Antihypertensive medicines are
particularly recommended if the systolic pressure is 160 mmHg
or more and/or the diastolic pressure is 100 mmHg or more.
There are different antihypertensive medicines and your doctor
will assess which type is best for you start on.
A single antihypertensive medicine may not be adequate and
others will be added one by one until good blood pressure
control is achieved. Unless it is necessary to lower the blood
pressure urgently, an interval of at least 4 weeks is usual
before adding in more treatment.
Antihypertensive medicines can have side effects. However,
it is important to continue with treatment. Discuss any side
effects with your doctor, as there are options of different
antihypertensive medicines which suit you better.
Treatment should be regularly reviewed. If you make lifestyle
changes and your blood pressure has returned to a normal level,
your GP may advise you to cut down or come off antihypertensive
medicines for a trial period.

Antihypertensive medicines
include:Thiazide diuretics ('water tablets') e.g.
bendroflumethiazide, chlortalidone, indapamide, metolazone
are usually the first choice antihypertensive medicine for
people over 55 years. They work by flushing excess water and
salt from your body via the urine. With long-term use, they
also open up the blood vessels.Beta-blockers e.g. atenolol, bisoprolol,
metoprolol, propranolol, work by making the heart beat more
slowly and with less force, so lowering the pressure in your
arteries. Some beta-blockers also block renin, a chemical
in the kidney that controls the loss of sodium and water.Angiotensin-converting-enzyme inhibitors (ACE inhibitors)
e.g. captopril, enalapril, lisinopril, perindopril, ramipril.
Blood pressure is controlled in part by angiotensin, a natural
chemical produced by the kidney. Angiotensin causes the blood
vessels to narrow and so raise the blood pressure. ACE inhibitors
lower your blood pressure by stopping the formation of angiotensin.
About a third of all people taking ACE Inhibitors get a persistent
dry cough. If this occurs, an alternative type of antihypertensive
medicine should be tried. Angiotensin II receptor antagonists e.g.
candesartan, losartan, valsartan work similarly to ACE Inhibitors.
Instead of blocking the formation of angiotensin II, they
prevent the chemical from working at its site of action.
They are an alternative for people who experience a cough
with ACE inhibitors.Calcium channel blockers e.g. amlodipine,
diltiazem, nifedipine, nicardipine, verapamil keep your blood
vessels relaxed and open, making it easier for blood to flow
through them. This lowers the blood pressure. Some calcium
channel blockers also make the heart beat more slowly.Alpha blockers e.g. doxazosin, prazosin,
terazosin keep the blood vessels relaxed and open, making
it easier for blood to flow through them. This lowers your
blood pressure.
Some people feel faint after taking the first few doses of
an alpha-blocker. For this reason, it is best to take the
first few doses at night just before going to bed. Also, the
doctor will usually start you on a low dose and gradually
increase the dose as you get used to it.

Medicines to reduce the risk
of heart attack and strokeStatins e.g. atorvastatin, fluvastatin, pravastatin,
rosuvastatin, simvastatin lower the blood cholesterol level
by preventing cholesterol from being made in the liver. For
people with high blood pressure, the aim is to reduce the
total blood cholesterol level to below 4 mmol/l or by 25%
of the original blood level whichever gives the greatest reduction.
Generally, the higher the blood cholesterol level, the greater
the risk of atherosclerosis (fatty deposits in the arteries).
Atherosclerosis causes narrowing of the arteries (blood vessels)
which when combined with high blood pressure can put you at
a greater risk of heart attack and stroke. Low dose aspirin
Taking low dose aspirin, usually 75mg, when you have high
blood pressure helps to reduce the risk of having a heart
attack or stroke.
Low dose aspirin reduces the 'stickiness' of platelets (tiny
particles in the blood that help the blood to clot). When
a large number of platelets stick to an atheroma (fatty deposit)
inside an artery, they can form a thrombosis (clot). If a
clot forms in an artery to the heart muscle, it can cause
a heart attack or in an artery to the brain, a stroke

Prevention

You can help treat and reduce your risk of developing high
blood pressure by making lifestyle changes:
eat a healthy, well-balanced diet, with less salt, lose weight
if necessary, exercise regularly, stop smoking, reduce your
alcohol and caffeine consumption to recommended levels.Regular
checks of your blood pressure are important, especially if
you have a family history of hypertension. Treatment can then
be started before complications have a chance to develop.